Method and apparatus for selecting core network in mobile communication system

ABSTRACT

A method and an apparatus for selecting a core network in a mobile communication system are disclosed. According to some aspects of the present disclosure, a method and apparatus are provided for selecting a core network which is appropriate to the type of user&#39;s subscribed service in a mobile communication system, without the need for re-routing.

CROSS-REFERENCE TO RELATED APPLICATION

The present application is a continuation of U.S. Pat. No. 11,265,809filed on Feb. 18, 2020, which a continuation of U.S. Pat. No.10,609,636, filed May 21, 2018, which is a continuation of InternationalApplication No. PCT/KR2016/012814, filed Nov. 8, 2016, which is basedupon and claims the benefit of priorities from Korean Patent ApplicationNos. 10-2015-0162790 and 10-2016-0140378, respectively filed on Nov. 19,2015 and Oct. 26, 2016. The disclosures of the above-listed applicationsare hereby incorporated by reference herein in their entirety.

TECHNICAL FIELD

The present disclosure in some embodiments relates to a method and anapparatus for selecting a core network individually configured accordingto the type of service subscribed to by a user in a mobile communicationsystem.

BACKGROUND

The statements in this section merely provide background informationrelated to the present disclosure and do not necessarily constituteprior art.

A mobile communication carrier can separate and operate a core networkfor each service for the sake of easiness of system operation and QoS(quality of service) protection. For example, a mobile communicationsystem may be composed of two core networks. One is a dedicated corenetwork which is dedicated to a specific service (for example, Internetof Things or IoT), and the other is a common core network used commonlyfor all other services. Operating a core network separately in thismanner enables to efficiently support different requirements for eachdevice and user. However, when a user terminal (User Equipment: UE)connects or attaches to the network, an appropriate core network needsto be selected based on the subscription information of the userterminal.

FIG. 1 is a flowchart of a conventional core network selection process.

Specifically, FIG. 1 shows, as a technology introduced by the 3GPPRelease 13 standard, selecting a service-specific core network by usingthe service information (usage type) included in the subscriptioninformation when the user terminal attaches to the network for the firsttime. When a terminal 10 attaches to the network (Step S110), a basestation (eNodeB) 20 cannot select a service-specific core network due tolack of information on the terminal. The base station 20 first selects abasic core network determined according to the setting, and transmits anattach request message (S112). A core network node ‘MME 1’ 30 a that hasreceived this message sends a location update request message to a homesubscriber server (HSS) 40 (S114), and receives, from the HSS 40, auser's subscribed service information (UE usage type) (S116). When theattached core network does not support the subscribed service, the ‘MME1’ 30 a selects another core network ‘MME 2’ 30 b that supports thesubscribed service (S118). Then, in order to re-direct the terminal tothe other selected core network, the ‘MME 1’ 30 a sends a NAS requestmessage to the base station 20 (S120). The subsequent process is thesame as the conventional location registration (attach/tracking areaupdate (TAU)) process.

The conventional method of selecting a core network needs a base stationto first attempt to attach a terminal to a preset default core network,and then re-direct the terminal device to another core network,resulting in two attempted attachments. This increases the time forattachment and overhead disadvantageously. In addition, the conventionalmethod provides the user with only a default type of service when therelevant network is not able to support the user's subscribed service,which prohibits efficient use of resources and impedes the improvementof user's QoS. Part of the deficiencies lies in the fact that a mobilitymanagement entity (MME) determines to select the core network and thatonly one service type is permitted for a single user.

DISCLOSURE Technical Problem

The present disclosure in some embodiments seeks to provide a method andapparatus for selecting an appropriate core network according to thetype of user subscribed service without re-routing in selecting the corenetwork in the mobile communication system.

Summary

In accordance with some embodiments of the present disclosure, a basestation apparatus for selecting a core network in a mobile communicationsystem, includes a service information acquisition unit, a terminalidentification information acquisition unit and a dedicated core networkselection unit. The service information acquisition unit is configuredto acquire a service information of a service to which a user subscribedfrom a service information database or a terminal device included in themobile communication system. The terminal identification informationacquisition unit is configured to acquire a terminal identificationinformation from the terminal device upon acquiring the serviceinformation of the service to which the user subscribed or a serviceinformation for selecting a core network from the service informationdatabase. The dedicated core network selection unit is configured toselect a dedicated core network to be used for providing a type ofservice to which the user subscribed, by using the service informationacquired by the service information acquisition unit.

In accordance with another embodiment of the present disclosure, aterminal device for selecting a core network in a mobile communicationsystem, includes a service information acquisition unit, a serviceinformation determining unit and a service information transmissionunit. The service information acquisition unit is configured to acquire,when a location registration of the terminal device is successful, aservice information of a service to which a user subscribed for aspecific type of service, or a service information for selecting a corenetwork, from a node of a dedicated core network dedicated to a specificservice, and to store the service information. The service informationdetermining unit is configured to determine whether the serviceinformation stored in the service information acquisition unit is valid.The service information transmission unit is configured to transmit theservice information stored to a base station apparatus, when the serviceinformation stored in the service information acquisition unit isdetermined to be valid.

In accordance with yet another embodiment of the present disclosure, aterminal device for selecting a core network in a mobile communicationsystem, includes a support service information acquisition unit, aservice support/nonsupport confirmation unit and a service informationtransmission unit. The support service information acquisition unit isconfigured to acquire, in response to a location registration of theterminal device, a support service information which is information on aservice supported by a dedicated core network, from a base stationapparatus. The service support/nonsupport confirmation unit isconfigured to perform a service support/nonsupport confirmation bycomparing the support service information with a prestored serviceinformation that is prestored in the terminal device and to confirmwhether or not the dedicated core network supports a service to which auser subscribed. The service information transmission unit is configuredto transmit the prestored service information to the base stationapparatus when the service support/nonsupport confirmation unit confirmsthat the dedicated core network supports the service to which the usersubscribed.

In accordance with some embodiments of the present disclosure, a methodof operating a base station apparatus for selecting a core network in amobile communication system, includes acquiring a service information ofa service to which a user subscribed from a service information databaseor a terminal device included in the mobile communication system, andselecting a dedicated core network to be used for providing a type ofservice to which the user subscribed, by using the service informationacquired by the acquiring of the service information.

In accordance with yet another embodiment of the present disclosure, amethod of operating a terminal device for selecting a core network in amobile communication system, includes acquiring, when a locationregistration of the terminal device is successful, a service informationof a service to which a user subscribed for a specific type of service,or a service information for use when selecting the core network from anode of a dedicated core network dedicated to a specific service, andstoring the service information, and determining whether the serviceinformation stored by the storing of the service information is valid,and transmitting, when the service information is determined to bevalid, the service information stored by the storing of the serviceinformation to a base station apparatus.

In accordance with yet another embodiment of the present disclosure, amethod of operating a terminal device for selecting a core network in amobile communication system, includes acquiring, in response to alocation registration of the terminal device, a support serviceinformation which is information on a service supported by a dedicatedcore network, or a service information for selecting a core network,from a base station apparatus, and performing a servicesupport/nonsupport confirmation comprising (1) comparing the supportservice information with a prestored service information that isprestored in the terminal device, and (2) confirming whether or not thededicated core network supports a service to which a user subscribed,and when the performing of the service support/nonsupport confirmationconfirms that the dedicated core network supports the service to whichthe user subscribed, transmitting the prestored service information tothe base station apparatus.

Advantageous Effects

As described above, according to some embodiments of the presentdisclosure, a method and apparatus are provided for selecting anappropriate core network according to the type of user subscribedservice without re-routing in selecting the core network in the mobilecommunication system.

According to some embodiments of the present disclosure, a base stationapparatus or base station directly selects the core network, therebypreventing the core network from being incorrectly selected.

According to some embodiments of the present disclosure, the userterminal device directly performs to select the core network, therebyfurther improving the scalability while solving the deficiencies of theprior art.

The present disclosure in some embodiments gives an advance notice ofthe type of service to be supported, thereby providing the user withbetter QoS while preventing increase in attachment time and messageoverhead due to incorrect selection of core network.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a flowchart of a conventional core network selection process.

FIG. 2 is a flowchart of a process of selecting a core network by a basestation according to at least one embodiment of the present disclosure.

FIG. 3 is a flowchart of a process of selecting a core network by a basestation according to another embodiment of the present disclosure.

FIG. 4 is a flowchart of a process, performed by a base stationaccording to at least one embodiment, for selecting a core network byusing a separate server.

FIG. 5 is a flowchart of a process of selecting a core network by aterminal according to at least one embodiment of the present disclosure.

FIG. 6 is a flowchart of a process of selecting a core network by usingservice information according to at least one embodiment of the presentdisclosure.

FIG. 7 is a flowchart of the operation of a terminal according to atleast one embodiment of the present disclosure.

FIG. 8 is a flowchart of the operation of a terminal according toanother embodiment of the present disclosure.

FIG. 9 is a schematic configuration diagram of a terminal and a basestation according to at least one embodiment of the present disclosure.

DETAILED DESCRIPTION

Hereinafter, some embodiments of the present disclosure will bedescribed in detail using exemplary drawings. As used herein the terms ‘. . . unit’, ‘module’, and the like refer to a unit for processing atleast one function or operation, which can be implemented by hardware,software, or a combination of hardware and software.

In order to clarify the explanation, the present embodiment is mainlyconcerned with a mobile communication system (Evolved Packet System orLong Term Evolution System) operating based on the 3GPP Release 13 andRelease 14 standards evolved from 3GPP LTE or LTE-Advanced system,although the present disclosure is not limited thereto, and can beapplied to the next generation mobile/wireless communication systembased on another communication system.

As shown in the example of FIG. 1 , the mobile communication systemaccording to at least one embodiment of the present disclosure includesa terminal (user equipment: UE) 10, a base station (eNodeB) 20, at leastone MME (mobility management entity) 30, and a home subscriber server(HSS) 40. In FIG. 1 , only components related to the present embodimentare shown, and other components may be further included.

The terminal 10 is an electronic device having a communication function.For example, the terminal may include various electronic apparatusesincluding a tablet PC, a laptop, a personal computer (PC), a personaldigital assistant (PDA), a portable multimedia player (PMP), a wirelesscommunication terminal, a smartphone, a mobile communication terminal, atelevision, a digital video disk (DVD) player, an audio system, arefrigerator, an air conditioner, a game console, a set-top box, medicaldevices, measuring devices, and such various electronic apparatuses.

The base station 20 may provide an interworking function between theterminal 10 and the core network (evolved packet core: EPC). The corenetwork includes a serving gateway (SGW, not shown), a packet datanetwork gateway: PDN GW (PGW, not shown), the MME 30, and the HSS 40.The base station 20 may support, for example, one or more cells ofGERAN, UTRAN, E-UTRAN, WB-E-UTRAN, NB-IoT and NR(New Radio).

The MME 30 is an element that performs signaling for supporting accessto the network connection of the terminal 10, allocation of networkresources, tracking, paging, roaming and handover, and that performscontrol functions. The MME 30 controls the functions of the controlplane related to the subscriber and the session management. In addition,the MME 30 performs functions such as security procedures,terminal-to-network session handling), and idle terminal locationmanagement.

The HSS 40 stores subscription information, subscriber authentication,and profile. When the terminal 10 attaches to the network, the HSS 40may transmit the subscription information of the relevant terminal 10and the like to the MME 30.

Deficiencies of the prior art shown in FIG. 1 , that is, an increase inattachment time due to two attempts of attachment, inefficient use ofresources, a decrease in QoS, etc., may occur due to the followingcauses. First, the MME 30 is supposed to receive the subscriptioninformation directly from the HSS 40 for selecting the core network.Second, only one service type is permitted for a single user.

In order to solve the deficiencies of the prior art, some embodiments ofthe present disclosure provides a method for the base station 20 todirectly select the core network. Hereinafter, a detailed descriptionwill be provided with reference to FIG. 2 .

FIG. 2 is a flowchart of a process, performed by a base stationaccording to at least one embodiment of the present disclosure, forselecting a core network by using service information base station.

The MME 30 is a core network node, and therefore, for convenience ofdescription, a method of selecting the MME 30 will be described below asan example method of selecting a core network according to someembodiments of the present disclosure. Thereafter, the method ofselecting other nodes (e.g., SGW, PGW, etc.) of the core network may beperformed by the MME using the received service information in the samemanner as the base station selects the MME.

Referring to FIG. 2 , in the present embodiment, the base station 20 maydirectly obtain the information for selecting the core network, i.e.,the MME 30, so as not to cause re-routing. Here, the information forselecting the core network refers to the service information to whichthe user subscribed.

Specifically, the user's subscribed service information includes theconventional usage type and it has a broader concept, including “slicetype information.” A slice is a unit of network logically dividedaccording to the purpose of use so as to satisfy specific needsdepending on the user. This is a concept that assumes a network in whichnetwork slice technology is implemented.

Slice type information is information about the dedicated core networkmapped to a particular service type (for example, including the corenetwork identifier and the like). The slice type information may bestored in the user terminal by being allocated to the user terminal orbeing transferred from the core network node to the user terminal.

In the following description of this specification, the user'ssubscribed service information is to be understood as including slicetype information, while a system using usage type is allowed to followthe usage type convention. For example, the service information may havea value that can identify a machine type communication (MTC) or Internetof Things (IoT) service, a mission critical service, a voice callservice, a mobile broadband service (MBB), and the like.

Referring to FIG. 2 , a mobile communication system according toembodiments of the present disclosure includes a service informationdatabase (DB) 50 in which the user's subscribed service information isstored. According to this embodiment, the service information DB 50 islinked to the base station 20, and thereby enables the serviceinformation DB 50 to receive the service information directly from theservice information DB 50 for selecting the core network withoutinvolving the MME 30. The direct selection of the core network by thebase station also improves the accuracy of selecting the core network.

When the terminal 10 first attaches to the base station 20 or when thereis no radio resource for signal transmission, the terminal 10 mayperform a random access procedure (RACH) for the base station 20 (StepS210). In addition, an initial process for radio resource control (RRC)connection setup is performed between the terminal 10 and the basestation 20 (S210).

The terminal 10 confirms whether it is necessary to use a dedicated corenetwork (DCN) (S212). Here, the dedicated core network refers to a corenetwork that is utilized to provide a certain type of service, i.e., oneof a plurality of services aforementioned with illustration, and it iscontrasted with common core network.

When it is necessary to use a dedicated core network, the terminal 10utilizes the RRC message in transmitting the identification information(e.g., IMSI) of the terminal 10 to the base station 20 with (S214).

The base station 20 attaches to the service information DB 50 totransmit the identification information of the terminal and to transmita message for requesting the user's subscribed service information (e.g.slice type information) (S216). In response, the service information DB50 provides the base station 20 with the service information mapped tothe identification information of the terminal (S218).

Using the obtained service information, the base station 20 selects adedicated core network (for example, MME) that is used for providing theuser's subscribed type of service (S220). For example, the base station20 may find the MME ID or MME Group Identifier (MMEGI) corresponding topart or all of the obtained slice type information. As another example,the base station 20 may select the MME by receiving MME informationafter making an MME inquiry to a separate server (for example, DSN:domain name system) with service information used as a parameter.

The base station 20 sends the selected MME 30 an initial UE messageincluding a non-access stratum (NAS) message received from the terminal10 (S222). The subsequent procedure is the same as the existing locationregistration (attach/tracking area update (TAU)) process.

In embodiments, the service information DB 50 may be implemented as a DBlimited to providing service information for selecting a core network,or it may be implemented as a additional function added to an existingDB (for example, HSS or AAA server) for storing user subscriptioninformation.

Although the embodiment shown in FIG. 2 can improve the accuracy ofselecting the core network, it needs complementary measures since theidentification information of the terminal is exposed to the basestation and it is necessary to interlock the service information DB witha large number of base stations. An embodiment according to the presentdisclosure with the complementary measures will be described withreference to FIG. 3 .

FIG. 3 is a flowchart of a process of selecting a core network by a basestation according to another embodiment of the present disclosure.

In the illustrated embodiment in FIG. 3 , the terminal 10 directlyobtains the user's subscribed service information, and the base station20 selects the core network by using the service information that theterminal 10 obtained. In other words, the base station 20 may obtain theservice information from the terminal 10 and use the obtained serviceinformation to select the dedicated core network mapped to the relevantservice.

Specifically, a core network may be selected using a conventionaltechnique (for example, DECOR; Dedicated Core Network) (S310). When theprocedure is performed for attaching the terminal 10 to the selectedcore network (MME, 30) and the attachment is accepted, the MME 30provides the user's subscribed service information through a NASacceptance message (S312).

In Step S312, the MME 30 may directly deliver the subscribed serviceinformation (e.g., Network Slice Type, Usage Type, DCN-ID, etc.)received from the HSS 40 to the terminal 10. Alternatively, the MME 30may transfer the service information to the terminal 10 in the form ofother information (e.g., one or more MMEGIs) that can be used whenselecting the MME. Here, the information provided by the MME 30 mayinclude not only information on the service type like the slice typeinformation but also a validity timer indicating the time during whichthe service information is valid.

The terminal 10 stores service information (e.g., slice typeinformation) acquired from the previously selected core network in astorage device (not shown) included in the terminal device (S314). Here,the service information may include not only information about theservice type, such as slice type information, but also a validity timerindicating a time during which the service information is valid.Additional description of the valid timer will be given below withreference to other drawings.

When there is a need to select a new dedicated core network which isdifferent from an existing core networks previously selected, theterminal 10 performs a random access process (RACH) with respect to thebase station 20. An initial process for radio resource control (RRC)connection setup is performed between the terminal 10 and the basestation 20 (S316). Thereafter, the terminal 10 transmits the storedservice information to the base station 20 through the RRC message(S318). The service information transmitted from the terminal 10 to thebase station 20 as described above is used by the base station 20 forselecting a new dedicated core network (S320).

FIG. 3 exemplifies the case where the base station can select a new MMEaccording to the service information received from the terminal. Thebase station 10 newly selects the MME 30 and transmits the firstterminal message including the NAS message to the selected MME 30(S322). Here, the initial terminal message includes slice typeinformation that the base station 20 received from the terminal 10, thatis, service information. Alternatively, the service information may bedirectly transmitted after being included in the NAS message that theterminal 10 transmits to the MME 30.

Upon receiving the initial terminal message, the MME 30 sends the HSS 40an Update Location Request message or Authentication Information Requestincluding the terminal device identification information (e.g., IMSI)(S324). As a result, the HSS 40 extracts user's subscribed serviceinformation, i.e., slice type information permitted to the terminal 10,includes the extracted information in an update acceptance (UpdateLocation Answer) message or Authentication Information Answer, andtransmits the message with information to the MME 30 (S326).

The MME 30 may finally decides whether to accept the use of the slicetype core network requested from the terminal 10 by using the slice typeinformation received from the HSS 40 (S328). Step S328 is a process forpreventing an error that may occur when a core network is selected onlywith the slice type information stored in the terminal 10. This canimprove the accuracy of selection of the core network.

The embodiment illustrated in FIG. 3 generates no rerouting after thenetwork attachment has occurred even once, but the initial networkattachment, in which the service information is not transmitted from theterminal to the base station, may involve rerouting. Therefore, anembodiment according to the present disclosure with the complementarymeasures will be described with reference to FIG. 4 .

FIG. 4 is a flowchart of a process, performed by a base stationaccording to at least one embodiment, for selecting a core network byusing a separate server.

The embodiment of FIG. 4 can compensate the aforementioned deficiency bypresetting the service information to the terminal 10 by using aseparate server 60. FIG. 4 shows that the service informationconfiguration server 60 exists as a separate unit in the mobilecommunication system, although not limited thereto. The server 60 mayalso be implemented along with another component into an integratedunit. For example, the service information configured by the serviceinformation configuration server 60 may be pre-configured at the time ofmanufacturing the terminal 10.

Referring to FIG. 4 , the terminal 10 may send the server 60 a serviceinformation request message including identification information of theterminal 10, attribute information (e.g., low priority access) of theterminal 10, and the like (S410). Step S410 may be omitted according tothe embodiment and is not an indispensable process.

The service information configuration server 60 configures serviceinformation suitable for the terminal 10, and transmits the configuredservice information to the terminal 10 through a Service InformationProvisioning message (S412). Again, the service information similarlyincludes slice type information. Step S412 may be performed by using theOpen Mobile Alliance-Device Management (OMA-DM) technology. In thatcase, the service information configuration server 60 may transmit theservice information by using the NAS management object (MO).

The terminal 10 stores the service information acquired from the serviceinformation configuration server 60 (S414). Thereafter, when thelocation registration (Attach/TAU) is necessary, as described above, theterminal 10 performs a random access process (RACH) with respect to thebase station 20. In addition, an initial process is performed for theRRC connection setting up between the terminal 10 and the base station20 (S416). Here, cases where the location registration is needed mayinclude where the terminal 10 deviates from the registered tracking area(TA), where the terminal 10 is out of the area or coverage of theoperator (PLMN: Public Land Mobile Network Identity), where the radioaccess technology (RAT) in use needs to be changed, and when receiving aDetach command from the network, and the like.

The terminal 10 transmits the service information (e.g., slice typeinformation) stored in the terminal 10 via the RRC message to the basestation 20 (S418). Step S416 and Step S418 are the same as thosedescribed in FIG. 3 , and the subsequent processes are also the same.

As described above, the conventional technology suffers from thedeficiency that only one usage type is provided to the user, and whenthe subscribed usage type is unusable, the user is only allowed toreceive the default service from the same operator. This deficiency is afactor that degrades the efficiency of use of the network when thenetwork is shared or when the terminal can directly select one from twoor more operators. This is true because, when the user is able to attachto both networks, e.g., operator A and operator B, it is effective toreceive the QoS of a dedicated service by selecting operator B ratherthan receiving the default service from operator A.

FIG. 5 is a flowchart of a process of selecting a core network by aterminal according to at least one embodiment of the present disclosure.

In this embodiment according to FIG. 5 , information on servicessupported by the network is notified before the terminal 10 performs theauthentication/attachment procedure, to avoid unnecessary servicenegotiation procedure. Further, if necessary, the terminal 10 maydirectly attach to another network that provides better service.

Specifically, referring to FIG. 5 , the base station 20 transmitsservice information supported by a dedicated core network (hereinafterreferred to as “support service information”) connected to itself to theterminal 10 (S510). In Step S510, the base station 20 may broadcast aplurality of support service information via a system information block(SIB). In another embodiment, Step S510 may render the base station 20to unicast a plurality of support service information via an RRCmessage.

In the case of the unicast method, the base station 20 may selectivelyconfigure the service information to be transmitted to the terminal 10taking account of information provided by the terminal 10 (e.g., UEradio capability or device property, etc.). When the terminal 10, whichhas already received the broadcast support service information, attachesto a specific cell and receives the support service information throughunicast, the terminal needs to preferentially apply the informationreceived through the unicast while the terminal attaches to that cell.

The support service information may be set in the base station 20 usingthe OAM function. Alternatively, the support service information mayalso be acquired from MME 30 in the process the base station 20 performsthe S1 setup procedure with the MME 30. More specifically, during the S1setup procedure, MME can provide the service information including thesupported services (DCN-IDs) to the base station.

Thereafter, the terminal 10 compares the support service informationacquired from the base station 20 with the service information stored inthe terminal 10 itself (S512). When the service information stored inthe terminal 10 corresponds to the support service information, theterminal 10 attaches by the corresponding slice type, and if it does notcorrespond, the terminal 10 selects other radio access technology (RAT)or another operator (PLMN: Public Land Mobile Network Identity) (S514).During this process, the terminal 10 takes into consideration all of thepriority by each slice type, the priority of RAT selection, and thepriority of operator selection. Thereafter, the process of the corenetwork attachment is the same as the process described above.

In this manner, the terminal 10 directly selects the core network, sothat the scalability can be improved.

FIG. 6 is a flowchart of a process of selecting a core network by usingservice information according to at least one embodiment of the presentdisclosure.

FIG. 6 shows an example in which the service information includes one ormore of service type information applicable to the terminal 10, a validtimer indicating a time during which the service type information isvalid, priority information, and PLMN identification information (PLMNID), so as to allow a flexible selection of core network.

Specifically, the service information configuration server 60 may addnot only slice type information but also PLMN identification informationand priority order information to the service information to be providedto the terminal 10 (S610). For example, the configuration provided maybe expressed as follows:

PLMN ID X ---- slice type 1 ---- priority 1 ---- slice type 2 ----priority 2

As described above, the terminal 10 may acquire the support serviceinformation from the base station 20 through the SIB or the RRC message(S612). The terminal 10 may select the slice type of the cell to attach,by using the service information acquired from the service informationconfiguration server 60 and the support service information (S614).

In Step S614, after collecting the cell information, the terminal mayselect, when selecting the cell to attach, the priority slice typehaving the highest priority among the slice types supported byattachable cells. In Step S614, the PLMN or RAT to which the terminal 10attaches may be changed, and the terminal 10 may be provided with atimer to operate to prevent too frequent change. Specifically, when theterminal 10 begins to receive service from the selected certain slicetype, it does not change the slice type until the timer expires exceptfor inevitable situations such as going outside the network coverage.

Steps S618 to S626 of FIG. 6 are the same as the steps described above,and therefore the description thereof is omitted.

Hereinafter, with reference to FIG. 7 and FIG. 8 , the operation of theterminal according to some embodiments of the present disclosure will bedetailed.

FIG. 7 is a flowchart of the operation of a terminal according to atleast one embodiment of the present disclosure.

FIG. 8 is a flowchart of the operation of a terminal device according toanother embodiment of the present disclosure.

First, the operation of the terminal device according to the embodimentshown in FIG. 7 will be described. When the location registration(Attach/TAU) of the terminal 10 succeeds, i.e., when the Attach/TAUacceptance message is received) with respect to the previously selecteddedicated core network, the terminal 10 receives, from the node (e.g.,MME) of the previously selected dedicated core network, the user'ssubscribed service information or the service information that is usedwhen selecting the core network, and stores the received information(S710). Here, the service information may include service typeinformation applicable to the terminal 10, and a valid timer indicatinga valid time of the service type information. The service typeinformation may also be called slice type information or dedicated corenetwork identifier.

The terminal 10 in Step S712 is able to initiate an effective timer forthe stored service type information if the service information includesthe valid timer. When the valid timer expires, the service typeinformation may be determined to be invalid.

Thereafter, when the location registration is needed again due to themovement or change in state of the terminal 10 (S714, Yes), the validityof the service information stored in the terminal 10 is determined(S716). Here, cases where the location registration is needed mayinclude where the terminal 10 deviates from the registered tracking area(TA), where the terminal 10 is out of the area or coverage of theoperator (PLMN), where the radio access technology (RAT) in use needs tobe changed, and when receiving a Detach command from the network, etc.

For example, the service information received by the terminal 10 fromthe core network is valid only for the operator corresponding to theservice information when it includes the PLMN information. Otherwise,when the service information does not contain the PLMN information inparticular, the terminal 10 considers the received service informationto be valid only for the registered PLMN.

Step S716 may include at least one of processes of (i) determiningwhether the existing dedicated core network previously attached has thesame PLMN identification information as that of the new dedicated corenetwork to attach, (ii) determining whether the terminal 10 does thelocation registration in a new area rather than the existing area wherethe previous registration occurred, and (iii) determining whether thereis service information for which the valid timer has not expired amongthe pieces of service information stored in the terminal 10. Here, thenew area may be one of a new tracking area (TA), a new routing area (RA)and a new public land mobile network (PLMN).

Upon determining that the stored service information is valid, theterminal 10 sends the base station 20 the stored service informationthat was received previously at the time of attachment of the basestation 20 (S718). Specifically, the terminal 10 may include the serviceinformation to be transmitted in an RRC Connection Setup Completemessage.

After Step S718, the terminal 10 performs the remaining processing oflocation registration (S722).

On the other hand, when the service information determination finds novalid service information, the terminal 10 operates using theconventional technology (e.g., 3GPP Rel-13 DECOR) (S720).

The following describes, with reference to FIG. 8 , a method ofoperating the terminal according to another embodiment of the presentdisclosure.

The terminal 10 obtains and stores the service information (S810). Here,the service information may include at least one of service typeinformation applicable to the terminal 10, a valid timer indicating atime during which the service type information is valid, priorityinformation, and PLMN identification information.

In Step S810, the terminal 10 may obtain the service information fromthe node (e.g., MME, SGSN, etc.) of the previously attached dedicatedcore network. Further, the terminal 10 may utilize at least one of theidentification information of the terminal 10 and the attributeinformation of the terminal 10, to obtain the service information fromthe service information configuration server 60 which configures serviceinformation suitable for the terminal 10. Depending on the embodiment,the service information may also be pre-configured in the terminal 10.

After Step S810, when the position registration is needed again due tothe movement or the change of state of the terminal 10 (S812, Yes), theterminal 10 may receive, from the nearby base station 20, information onone or more supported services that are supported by the dedicated corenetwork attached to the base device 20 (S814). Here, the support serviceinformation may be broadcasted by the base station 20 through a systeminformation block (SIB). As another example, support service informationmay also be unicast through an RRC message. In the case of the unicastmethod, the base station 20 mat select the service information to betransmitted to the terminal 10 taking account of information provided bythe terminal 10 (e.g., UE radio capability or device property, etc.).

The support service information may be set in the base station 20 byusing the OAM function. Alternatively, it may be obtained from the MME30 in the process of the base station 20 performing the procedure of S1setup with the MME 30.

The terminal 10 compares the information of the one or more supportedservices with the service information stored in the terminal 10, andconfirms whether the dedicated core network to which the terminal 10previously attached supports the service subscribed by the user (S816).Specifically, the terminal 10 may compare the support serviceinformation and the stored service information based on the priorityorder information included in the service information. Upon comparison,the highest priority service information among the service informationthat matches the support service information, may be selected and passedto the base station (S818). At this time, the terminal 10 may includethe highest priority service information in the RRC Connection SetupComplete message and transfer the resultant message to the base station20. Thereafter, the terminal 10 performs the remaining procedure oflocation registration (S822).

In addition, when the comparison finds that the highest priority serviceinformation among the service information stored in the terminal 10 doesnot match the support service information (S816, NO), the terminal 10may select a cell of another base station in order to select anotherdedicated core network that supports the highest priority serviceinformation (S820). Here, in order to select a cell of another basestation, the terminal 10 may change the RAT, the base station or thePLMN.

Hereinafter, with reference to FIG. 9 , terminal 10 and base station 20according to some embodiments of the present disclosure will bedescribed.

FIG. 9 is a schematic configuration diagram of a terminal and a basestation according to at least one embodiment of the present disclosure.

A base station 20 of a mobile communication system according to someembodiments includes a service information acquisition section 22, aterminal identification information acquisition section 24 and adedicated core network selection section 26. FIG. 9 schematically showsthe relevant components only, and in addition to the illustratedcomponents, other general-purpose components may further be included. Inaddition, FIG. 9 shows that each component exists as a separate unit,although not limited thereto, and they may also be implemented in asingle integrated device including all of the respective functions.

The service information acquisition unit 22 acquires the user'ssubscribed service information from a service information database (notshown) included in the mobile communication system or from the terminal10.

In the case of acquiring the service information directly from theterminal 10, the service information may be prestored in the terminal 10to be transmitted to the base station 20.

Specifically, when acquiring the service information from the serviceinformation DB, where a dedicated core network needs to be used, theterminal 10 uses the RRC message to transmit the identificationinformation of the terminal 10 (for example, IMSI) to the base station20. The terminal identification information acquisition unit 24 acquiresidentification information of the terminal transmitted from the terminal10.

The base station 20 attaches to the service information DB to transmitthe identification information of the terminal, and transmits a messagerequesting the user's subscribed service information (e.g., slice typeinformation). As a result, the service information acquisition unit 22acquires, from the service information DB, the service informationmapped to the identification information of the terminal.

Using the acquired service information, the dedicated core networkselection unit 26 selects a dedicated core network (for example, MME)that is used for providing the user's subscribed type of service. Forexample, the dedicated core network selection unit 26 may search for theID of the MME corresponding to some or all of the acquired slice typeinformation, or an MME Group Identifier (MMEGI), or it may ask aseparate server (e.g., DSN: Domain Name System or the like), and therebyselects the MME.

A terminal 10 according to some embodiments of the present disclosureincludes a service information acquisition unit 12, a serviceinformation determining unit 14 and a service information transmissionunit 19.

When the location registration of the terminal is successful withrespect to the previously selected dedicated core network used forproviding a specific type of service, the service informationacquisition unit 12 acquires and stores the user's subscribed serviceinformation from the previously selected dedicated core network. Here,the service information may include service type information applicableto the terminal 10 and a valid timer indicating a time during which theservice type information is valid.

When it is necessary to select a new dedicated core network, the serviceinformation determining unit 14 determines whether the stored serviceinformation in the service information acquisition unit 12 is valid.

The service information determining unit 14 may perform at least one ofprocesses of (i) determining whether the new dedicated core network isthe same as the previously selected dedicated core network, (ii)determining whether the terminal 10 registered at the time of acquiringthe service information from the previously selected dedicated corenetwork, has the same location as that of the terminal 10 to beregistered in case of attaching to a new dedicated core network, and(iii) determining whether there is service information for which thevalid timer has not expired among the pieces of service informationstored in the terminal 10.

In other words, the service information determining unit 14 maydetermine at least one of (i) whether the existing dedicated corenetwork previously attached has the same PLMN identification informationas that of the new dedicated core network to attach, (ii) whether theterminal does the location registration in a new area rather than theexisting area where the previous registration occurred, and (iii)whether or not the valid timer included in the service informationexpires.

The service information determined by the service informationdetermining unit 14 may be reconfirmed as to its validity by the corenetwork node which has received the location registration requestmessage of the terminal 10.

Upon determining by the service information determining unit 14 that thestored service information from is valid, the service informationtransmission unit 19 transmits the stored service information in theservice information acquisition unit 12 to the base station 20.Specifically, the terminal 10 may include the service information to betransmitted in an RRC Connection Setup Complete message.

A terminal 10 according to another embodiment of the present disclosureincludes a support service information acquisition unit 16 and a servicesupport/nonsupport confirmation unit 18 in addition to the serviceinformation acquisition unit 12 and the service information transmissionunit 19.

The service information acquisition unit 12 according to the presentembodiment acquires and stores the user's subscribed serviceinformation. Here, the service information may include at least one ofservice type information applicable to the terminal 10, a valid timerindicating a time during which the service type information is valid,priority information, and PLMN identification information.

The supported service information acquisition unit 16 acquires, whenthere is a need for the location registration of the terminal 10,support service information which is information on the servicessupported by the dedicated core network, from the base station 20. Here,cases where the location registration is needed may include where theterminal 10 deviates from the TA, where the terminal 10 is out of thecoverage or area of the operator (PLMN), where the RAT in use needs tobe changed, and when receiving a Detach command from the network, andthe like.

The service support/nonsupport confirmation unit 18 compares informationon one or more of supported services with the service information storedin the service information acquisition unit 12, to confirm whether theexisting dedicated core network that is previously attached supports theservice to which the user subscribed. Here, the service informationstored in the service information acquisition unit 12 (i.e., prestoredservice information) may be either acquired from an existing dedicatedcore network node that underwent a previous location registration or aseparate server, or pre-configured in the terminal 10. The separateserver may configure service information suitable for the terminal 10 byusing at least one of identification information and attributeinformation of the terminal 10.

The service support/nonsupport confirmation unit 18 may compare thesupport service information and the prestored service information basedon the priority order information included in the service information.

Based on the result of the comparison by the service support/nonsupportconfirmation unit 18, the service information transmission unit 19 mayselect the highest priority service information among pieces of theprestored service information that match the support serviceinformation, and transmit the highest priority service information tothe base station 20.

On the other hand, the terminal 10 may select a cell other than a cellof the base station 20, when the comparison by the service informationconfirmation section 18 indicates that the highest priority serviceinformation among the pieces of the prestored base information does notmatch the support service information, in order to select anotherdedicated core network that supports the highest priority serviceinformation.

FIGS. 1 to 8 are described as sequentially performing the respectivesteps, although they are not necessarily limited thereto. Specifically,various modifications are possible by changing the sequences illustratedin FIGS. 1 to 8 or by performing two or more of those steps in parallel,without departing from the gist and nature of the embodiments of thepresent disclosure, and hence the steps in FIGS. 1 to 8 are not limitedto the illustrated chronological sequences.

Although exemplary embodiments of the present disclosure have beendescribed for illustrative purposes, those skilled in the art willappreciate that various modifications, additions and substitutions arepossible, without departing from the idea and scope of the claimedinvention. Therefore, exemplary embodiments of the present disclosurehave been described for the sake of brevity and clarity. The scope ofthe technical idea of the present embodiments is not limited by theillustrations. Accordingly, one of ordinary skill would understand thescope of the claimed invention is not to be limited by the explicitlydescribed above embodiments but by the claims and equivalents thereof.

INDUSTRIAL APPLICABILITY

As described above, the present disclosure in some embodiments isapplied to a field of selecting a core network individually configuredaccording to the type of service that a user subscribed to in the mobilecommunication system, and provides better QoS to the user whilepreventing an increase in attachment time and message overhead withoutthe need for re-routing.

The invention claimed is:
 1. A terminal device for selecting a core network in a mobile communication system, the terminal device comprising: a service information acquisition unit configured to acquire, when a location registration of the terminal device is successful, a service information of a service to which a user subscribed for a specific type of service from a node of a dedicated core network dedicated to a specific service, and to store the service information; a service information determining unit configured to determine whether the stored service information is valid; and a service information transmission unit configured to transmit, when the stored service information is determined to be valid, the stored service information to a base station apparatus, wherein the dedicated core network sends a request message to a home subscriber server when the dedicated core network receives the service information from the base station apparatus, and wherein the dedicated core network receives an answer message including the service information which the user subscribed from the home subscriber server when the home subscriber server receives the request message from the dedicated core network.
 2. The terminal device of claim 1, wherein the service information comprises: at least one of a service type information applicable to the terminal device, a valid timer indicating a time during which the service type information is valid, and a Public Land Mobile Network Identity (PLMN) identification information.
 3. The terminal device of claim 1, wherein the service information determining unit is configured to determine at least one of: whether a previously accessed dedicated core network and a new dedicated core network to be accessed have a same PLMN identification information, whether or not a valid timer included in the service information expires, or whether the terminal device performs the location registration in a new area rather than an existing area where a previous registration occurred.
 4. The terminal device of claim 1, wherein the service information includes a dedicated core network identifier.
 5. The terminal device of claim 1, wherein the terminal device determines whether the service information is valid and transmits the service information to the base station apparatus, when registration to a new location is required. 